您可以通过调试器找到它。下面是一个调试器查看的代码的开头:
CPU Disasm
Address Command Comments
00401000 CALL 0040100C ; call main
00401005 PUSH 0 ; /ExitCode = 0
00401007 CALL <JMP.&kernel32.ExitProcess> ; \KERNEL32.ExitProcess
0040100C PUSH EBP ; main
0040100D MOV EBP,ESP
0040100F ADD ESP,-4
00401012 MOV DWORD PTR SS:[LOCAL.1],0 ; dewit = 0
00401019 PUSH DWORD PTR SS:[LOCAL.1] ; /Arg1 => 0
0040101C CALL 00401024 ; print
00401021 LEAVE
00401022 RETN
所以print
叫(请记住,print
是一个宏观的,所以它的扩展编译一次)。 Remeber你推0至print
:
CPU Disasm
Address Command Comments
00401024 PUSH EBP ; print (guessed Arg1)
00401025 MOV EBP,ESP
00401027 ADD ESP,-0C
0040102A PUSH -0B ; /StdHandle = STD_OUTPUT_HANDLE
0040102C CALL <JMP.&kernel32.GetStdHandle> ; \KERNEL32.GetStdHandle
00401031 MOV DWORD PTR SS:[LOCAL.1],EAX
00401034 PUSH DWORD PTR SS:[Arg1] ; /Arg1 => [Arg1] *** push 0 ***
00401037 CALL 00401060 ; \so.00401060
见行0x00401034
,0被推为一个调用的参数。
让我们来看看代码:
CPU Disasm
Address Command Comments
00401060 MOV EAX,DWORD PTR SS:[Arg1] ; eax = 0
00401064 LEA EDX,[EAX+3]
00401067 PUSH EBP
00401068 PUSH EDI
00401069 MOV EBP,80808080
0040106E /MOV EDI,DWORD PTR DS:[EAX] ; trying to dereference [0]...
代码功能是在地址0(又名空指针错误),这是一个很大的阅读,不,不。
看着print
宏在macros.asm
,看来这个宏没有做任何格式化,你应该用printf
。
您的代码固定的(你需要printf
宏,msvcrt.inc
和msvcrt.lib
仍处于macros.asm
定义):
.486
.model flat, stdcall
option casemap :none
include \masm32\include\windows.inc
include \masm32\include\msvcrt.inc
include \masm32\macros\macros.asm
include \masm32\include\masm32.inc
include \masm32\include\gdi32.inc
include \masm32\include\user32.inc
include \masm32\include\kernel32.inc
includelib \masm32\lib\msvcrt.lib
includelib \masm32\lib\masm32.lib
includelib \masm32\lib\gdi32.lib
includelib \masm32\lib\user32.lib
includelib \masm32\lib\kernel32.lib
includelib \masm32\lib\masm32.lib
.data
format_string db "value: %d", 0
.code
start:
call main
exit
main proc
LOCAL dewit:DWORD
mov dewit, 0
print "printing value: "
printf ("value: %d", dewit)
ret
main endp
end start
大致没有任何相同的代码包括:
; compile and link with:
; ml test.asm /link /subsystem:console /defaultlib:kernel32.lib /defaultlib:msvcrt.lib
.686
.model flat, stdcall
option casemap: none
ExitProcess PROTO STDCALL :DWORD
externdef _imp__printf:PTR c_msvcrt
crt_printf equ <_imp__printf>
.data
fmt db "value: %d", 0
.code
start:
call MyFunc
invoke ExitProcess, 0
ret
MyFunc proc
LOCAL foo:DWORD
mov foo, 42
push foo
push offset fmt
call crt_printf
ret
MyFunc endp
end start
我也完全同意@Jester:
另外,consi明镜不使用辅助功能,直到你可以用手 做到这一点,并了解汇编做
宏是伟大的,但除非你能理解他们做什么,实现手工一样,你应该避免使用它们。他们从初学者眼中隐藏太多东西。
'MOV [DEWIT],0 高级宏观帮助描述也许'MOV字PTR [DEWIT] 0'?还要定义“_didn't work_”。 – Jester
没有工作 - 即它遇到了错误,我想..该程序'停止工作'在那一点 – daniel
这是不够的信息,提供[mcve]。您也可以查看生成的汇编代码。另外,考虑不要使用帮助器功能,直到您也可以手动完成,并了解汇编器在做什么。 – Jester